Despite the development of drugs that preferentially target tumor cells without harming normal tissues, delivery of these drugs to brain tumors remains a major challenge because of difficulty in penetrating the blood-brain barrier (BBB). Astrocytomas are the most common group of primary brain tumors. Grade III astrocytomas or anaplastic astrocytomas (AA), and grade IV astrocytomas, or glioblastoma multiforme (GBM) tumors have a poor prognosis due to their aggressive growth and resistance to available therapies. Present therapies rely on early detection and the standard treatment of AA and GBM still consists of surgical resection, radiation therapy and chemotherapy. Although chemotherapy may increase the survival of patients with low grade gliomas to 5 to 10 years, this increase is only a couple of months in cases of GBM. GBMs are among the most lethal and intractable of human tumors, and drug resistance is one of the major obstacles to their successful treatment. Until now, no therapeutic modality has substantially changed the outcome of patients with GBM, which is therefore considered incurable. Hashizume et al. (2008) Neuro-Oncology 10:112-120.
Clearly there is a great need for new therapeutic strategies that will provide efficient drug delivery to the brain tumors and other cancers that require delivery of therapeutic agents across the BBB. This invention satisfies this need and provides related advantages as well.